Palladium-Catalyzed Synthesis of Indanone via C-H Annulation Reaction of Aldehydes with Norbornenes.

A novel methodology for the synthesis of indanone derivates has been developed. The palladium-catalyzed annulation reaction of o-bromobenzaldehydes with norbornene derivatives is achieved through extremely concise reaction processes. The indanone skeleton was established directly via C-H activation of the aldehyde group under a mild reaction condition. This method is simple and practical, which simplified the traditional synthesis method for the rapid construction of indanone.

Palladium-Catalyzed Direct Esterification via C-H Bond Activation of Aldehydes.

A concise and highly efficient synthesis method of direct esterification of aldehydes via Pd-catalyzed C-H bond activation of aldehyde group has been developed. The strategy avoids the preoxidation step of aldehyde or use of condensing agents in ester synthesis, which is not only applicable to various alcohols but also suitable for the esterification of phenolics which are usually difficult to be esterified. The methodology has the significant advantages of broad substrate scope, mild reaction conditions, and nonrequirement of additional oxidants.

Palladium-catalyzed and alcohol-enabled transformation to synthesize benzocyclic ketones.

Catalytic carbonyl formation ranks as one of the most important synthetic methodologies. Herein, a highly effective palladium-catalyzed and alcohol-promoted transformation of nitriles to synthesize benzocyclic ketones is described. It provides a straightforward access to potentially valuable indanone compounds in high yields in the presence of alcohol. It avoided the usage of carbon monoxide or an additional hydrolysis procedure.

Identification of avian flapping motion from non-volant winged dinosaurs based on modal effective mass analysis.

The origin of avian flight is one of the most controversial debates in Paleontology. This paper investigates the wing performance of Caudipteryx, the most basal non-volant dinosaur with pennaceous feathered forelimbs by using modal effective mass theory. From a mechanical standpoint, the forced vibrations excited by hindlimb locomotion stimulate the movement of wings, creating a flapping-like motion in response. This shows that the origin of the avian flight stroke should lie in a completely natural process of active locomotion on the ground. In this regard, flapping in the history of evolution of avian flight should have already occurred when the dinosaurs were equipped with pennaceous remiges and rectrices. The forced vibrations provided the initial training for flapping the feathered wings of theropods similar to Caudipteryx.

New lead-free perovskite Rb7Bi3Cl16 nanocrystals with blue luminescence and excellent moisture-stability.

The development of nontoxic and stable all-inorganic perovskite nanocrystals (NCs) represents a major challenge to unlock widely practical applications in photoelectric fields. It is an effective strategy to discover nontoxic metal perovskite nanocrystals (NCs) with excellent optical properties. In addition, it has been proved that alkali metals such as rubidium (Rb) and potassium (K) have a good influence on improving the optical performance of perovskites. Hence, we reported new lead-free perovskite Rb7Bi3Cl16 single crystals, which displayed a zero-dimensional cluster structure and were composed of two kinds of octahedra with different distortions. At the same time, we synthesized its NCs, which showed a blue emission at 437 nm with a PLQY of 28.43% and presented a good optical and moisture stability for one month. The excellent moisture-stability might be attributed to their much higher ratio of Rb atoms and the ideal [BiCl6]3- octahedra on the surface, which are beneficial to form an inorganic BiOCl shell to protect the Rb7Bi3Cl16 NCs from moisture attack.

Syntheses, crystal structures and optical properties of two one-dimensional germanophosphates: HRb3Ge2(HPO4)6 and CsGe(HPO4)2(OH).

Germanophosphates, as a young class of metal phosphates, have been less reported but might possess more diverse structural types and potential applications. Here, two one-dimensional (1D) alkali-metal germanophosphates (GePOs), namely, hydrogen hexakis(µ-hydrogen phosphato)digermaniumtrirubidium, HRb3Ge2(HPO4)6 (1), and caesium bis(µ-hydrogen phosphato)(µ-hydroxido)germanium, CsGe(HPO4)2(OH) (2), have been prepared by the solvothermal method. Compound 1 shows 1D [Ge(HPO4)6]∞ chains along the c axis formed by GeO6 octahedra and PO4 tetrahedra, with Rb+ cations dissociated between the chains. Compound 2 also exhibits 1D [Ge(HPO4)4(OH)2]∞ chains constructed from adjacent Ge(HPO4)4(OH)2 octahedra, with Cs+ cations dissociated between the chains. XRD, TGA, IR and UV-Vis-NIR absorption spectra are presented and discussed for both compounds.

Tuning optical properties of perovskite nanocrystals by supermolecular mercapto-ß-cyclodextrin.

This study reports a host-guest interaction strategy for systematically manipulating the optical properties of cesium lead halide perovskite nanocrystals (CsPbBr3 NCs) by protectant-mediated mercapto-ß-cyclodextrin (SH-ß-CD). The fluorescence of CsPbBr3 NCs can be adjusted over 405-510 nm with the quantum yields (QY) maintained at 50-90%.

[Highlights on the design procedure of corneal refractive surgery].

Corneal refractive surgery, especially excimer laser corneal refractive surgery, has been used nearly 20 years in China. As the development of high technology and the change of life style, people who received refractive surgery not only demands good visual acuity but also good visual quality. In recent years, more and more new techniques and equipments have sprung up in this field. Therefore, this provides more approaches for surgeon to design the surgical plan and meet patients' needs to see clearly and comfortably. In this article, the author minutely dissects the importance and influence of the design procedure from the perspective of scotopic vision (such as; design of thin cornea, severe astigmatism, scotopic large pupil size, and special corneal shape) and personalized surgical parameters.